Congenital factor XI deficiency with multiple tooth extractions (Case report)

Congenital factor XI deficiency (CFXI) is a rare blood disorder that occurs in one of every one million individuals. Given its rarity, there are very few reports of surgical procedures performed in the oral region CFXI patients. The present study reports the case of a 43-year-old man with CFXI who experienced multiple tooth extractions. It also conducted a review of the literature and treatment outline. We preoperatively administered fresh frozen plasma (FFP) before the tooth extraction and continued to transfuse FFP at the rate of 2 units per day from day 1 to 4 of admission. The extractions were divided into two parts, maxillary and mandibular and the teeth extracted on days 2 and 4 of admission. The patient was discharged on day 6 of admission because there was good progress and no postoperative bleeding. Therefore, it was possible to perform multiple tooth extractions without abnormal bleeding in the oral cavity; the chance of bleeding was reduced by administering FFP and increasing local hemostasis in CFXI patients.

Normal aPTT in children with mild factor XI deficiency

It has been suggested that persons with factor XI deficiency can have a normal activated partial thromboplastin time (aPTT). This notion is based on limited data, especially in children. Because of the central role the aPTT plays in diagnostic algorithms for bleeding disorders, it is important to know if a normal aPTT eliminates the need for factor XI activity testing. Our institutional database contains seven children with factor XI deficiency, of whom four have a normal aPTT. This supports the hypothesis that children with factor XI deficiency can have a normal aPTT. Clinicians may wish to consider this evidence when evaluating children with abnormal bleeding.

The hemostatic role of factor XI

Coagulation factor (F)XI has been described as a component of the early phase of the contact pathway of blood coagulation, acting downstream of factor XII. However, patients deficient in upstream members of the contact pathway, including FXII and prekallikrein, do not exhibit bleeding complications, while FXI-deficient patients sometimes experience mild bleeding, suggesting FXI plays a role in hemostasis independent of the contact pathway. Further complicating the picture, bleeding risk in FXI-deficient patients is difficult to predict because bleeding symptoms have not been found to correlate with FXI antigen levels or activity. However, recent studies have emerged to expand our understanding of FXI, demonstrating that activated FXI is able to activate coagulation factors FX, FV, and FVIII, and inhibit the anti-coagulant tissue factor pathway inhibitor (TFPI). Understanding these activities of FXI may help to better diagnose which FXI-deficient patients are at risk for bleeding. In contrast to its mild hemostatic activities, FXI is known to play a significant role in thrombosis, as it is a demonstrated independent risk factor for deep vein thrombosis, ischemic stroke, and myocardial infarction. Recent translational approaches have begun testing FXI as an antithrombotic, with one promising clinical study showing that an anti-sense oligonucleotide against FXI prevented venous thrombosis in elective knee surgery. A better understanding of the varied and complex role of FXI in both thrombosis and hemostasis will help to allow better prediction of bleeding risk in FXI-deficient patients and also informing the development of targeted agents to inhibit the thrombotic activities of FXI while preserving hemostasis.